§ 16. Parasitic mushrooms
Rice. 51. Pathogenic fungi on plants
Smut. Different types of this fungus can infect cereals: wheat, oats, barley, millet, corn. Most often, smut spores fall on healthy grains during harvesting and threshing and remain on them until sowing. Together with the grain, the spores fall into the ground and germinate in the threads of the mycelium. The fungus penetrates into the seedlings of cereal plants and grows inside the stem, feeding on its juices. By the time of flowering of cereals, the mycelium of the smut fungus reaches the ear. Here it grows strongly, forms a mass of spores, destroys grains and turns them into black dust. Spikelets become like charred firebrands. To destroy the smut spores, the grain must be treated with special preparations before sowing. The smut can affect not only cereals, but also other plants.
Ergot. Ergot fungus settles on some grain crops. In affected plants, healthy grains turn into poisonous black-violet horns, dense plexuses of ergot mycelium filaments. Once in food with flour, they can cause severe poisoning.
These fungi destroy the wood of trees, causing great harm to forestry, gardens and parks. Their spores enter the tree through wounds that appear in the bark when branches break, frost cracks, sunburn and other damage. The spores germinate into the mycelium, which spreads through the wood, destroys it, makes it rotten.
The fruit bodies of the tinder fungus are shaped like a hoof (Fig. 52). They usually appear on the bark of a tree a few years after infection, located on the trunks one above the other in the form of shelves. On the underside of the fruiting body, spores ripen in small tubules. Most tinder fungi have perennial fruiting bodies.
Rice. 52. Polypore mushrooms
Hollows appear in the trunks of trees affected by tinder fungus, they become brittle and break easily. The life span of a tree is greatly reduced.
When a tree dies, the tinder fungus continues to live on dead wood, destroying it. That is why it is impossible to use tree trunks affected by tinder fungi, and the materials obtained from them in the construction of various structures.
Rice. 53. Leaves and tubers of potatoes affected by late blight
A dangerous disease, potato cancer is also caused by a fungus. With potato cancer, growths appear as a result of tissue growth on stems, leaves, and tubers. Tubers with signs of cancer are unsuitable for food or livestock feed.
Fungi that cause black rot disease live on potato tubers. Other fungi infect the leaves, young shoots and fruits of the gooseberry, forming a white powdery coating, the so-called powdery mildew. If mushrooms (scab) settle on apples, the fruits become covered with flaky spots and then crack.
New concepts
Smut. ergot. tinder fungus
Tasks
Based on the study of the material of the paragraphs and additional literature, compose a message "The variety of fungi and their significance in nature and human life."
Mushrooms are of great importance in nature and play an essential role in human life. Destroying the remains of plants and animals, fungi participate in the cycle of substances in nature and in the formation of a fertile soil layer. Valuable medicines are obtained from some mushrooms. Edible mushrooms are edible. They are necessary in the manufacture of bread, cheeses, winemaking, etc.
